Question

求c/c++读取32位带alpha通道bmp并返回指向bmp的位图数据的代码，请高手指导指导。

尽量别借用mfc,由于对mfc还不是很了解，对于一些类库，如cimg,cximage，opencv,gdi+这些，能少用尽量少用。

Answer 1

turns a 16 or 32 bit bitfield image into a RGB image
void CxImage::Bitfield2RGB(BYTE *src, WORD redmask, WORD greenmask, WORD bluemask, BYTE bpp)
{
switch (bpp)
{
case 16:
break;
case 32:
{
// dword aligned width for 32 bit image
long effwidth4 = head.biWidth * 4;
long y4, y3, x4, x3;
BYTE * p = info.pImage; //指向位图像素数据的指针
// scan the buffer in reverse direction to avoid reallocations
for (long y=head.biHeight-1; y>=0; y--)
{
y4 = effwidth4 * y;

//对于高于8位以上的人位图info.dwEffWdith =
//(((24 * m_bmiHead.biWidth) + 31) / 32 * 4)
y3 = info.dwEffWidth * y;
for (long x = head.biWidth-1; x >= 0; x-- )
{
x4 = 4 * x + y4;
x3 = 3 * x + y3;
p[ x3] = src[ x4];
p[1+x3] = src[1+x4];
p[2+x3] = src[2+x4];
}
}
}

}
return;
}

追问

若是不借用CxImage类库，而只在控制台下，进行操作，这个函数也可以通用？